1. Field of the Invention
The present invention relates to a light apparatus capable of emitting light of multiple wavelengths using a nanometer fluorescent material, a light device and a manufacturing method thereof, and more particularly, to a semiconductor photoelectric device utilizing a nanometer fluorescent material to emit light.
2. Description of the Related Art
A light emitting diode (LED) is a photoelectric device that automatically emits light when electrically connected. Small, electrically efficient and good for initial driving, LEDs are widely used in general illumination, large billboards, and backlight sources for monitors.
At present, according to the semiconductor materials of which they are made, LEDs are divided into different families, namely GaAs, GaAs1-xPx and GaP. In addition, nitrogen-doped semiconductor materials of GaAs1-xPx or GaP families produce rays of multiple colors. In general, light emitted by an LED is characterized by a monochromatic wavelength which depends on the variation of energy involved in light-emitting electron transfer. The lights of wavelengths in use include infrared, red light, green light, yellow light and blue light. Human beings can see lights of different colors because the human eye perceives three different colors of light, namely red light, green light and blue light, which are collectively known as “primary colors” (RGB).
With juxtaposed LEDs of red wavelength, green wavelength and blue wavelength respectively, light of any other color is produced by means of mixing. The U.S. Pat. No. 5,995,070 discloses a displaying device comprising juxtaposed light sources wherein each pixel is composed of diodes of a red light source, a blue light source and two green light sources.
White light produced by mixing light sources of different wavelengths as mentioned above has problems about hue and brightness dispersion, thus it is rather difficult to produce the intended white light. In addition, since the light source of white light is composed of diodes of different electrical properties which have to be controlled by appropriate driving circuits respectively, the design of the system is complex.
Furthermore, the U.S. Pat. No. 6,614,179 discloses a method for producing white light that involves using an LED to emit blue light which, in turn, excites phosphor so that the excited phosphor emits yellow light, and then the two light sources combine to form white light by means of mixing, wherein the wavelength of the blue light ranges between 420 nm and 490 nm, and the phosphor is composed of {[(Y, Gd)Sm](AlGa)O:Ce}. But the white light produced by the method hardly expresses the real colors of an object, or, in other words, its color temperature is relatively high and thus its color rendering index is unsatisfactory.
Therefore, to develop white light of a high color rendering index, it is necessary to control or regulate the proportions of individual color lights in the light emitted by the light sources so that the emitted light approximates daylight in terms of the proportions of constituents, and in consequence colors of an object illuminated by the emitted light look vivid. Beside, as regards fluorescent materials, the focus of their research and development is the constituents of yttrium aluminum garnet (YAG) crystal (molecular formula: X3(A3B2)O12) for the time being, for example, Y3(Al3Al2)O12, (Y3-xCex)Al5O12, (Y2.9Tb0.05)Al5O12, and (Y2.95-aCe0.05Gda)(Al5-bGab)O12 in YAG phosphor structure.
In short, the market is urgently in need of a light apparatus that not only emits light similar to daylight in terms of proportions of constituents but also features high luminance efficiency and adequate brightness.